The present invention relates generally to temperature sensing devices. More particularly, the present invention relates to an automatic system for providing a warning to a truck driver when his refrigerated load has warmed to an unacceptable temperature.
As will be appreciated by those skilled in the art, trucks equipped to haul various food products long distances must be equipped with appropriate refrigeration capabilities. Like other mechanical systems, the refrigeration units employed with over-the-road trucks may periodically break down or otherwise require minor repairs or maintenance. Unfortunately, when refrigeration problems occur in an unforeseen fashion or at an unexpected time, the refrigerated contents of the truck may perish if critical repairs are not effectuated within predetermined time limits. Therefore, where an early warning of a temperature rise is provided, the trucker may save his load and avoid the otherwise costly losses associated with spoilage.
Previously the internal temperature of refrigerated truck compartments has been monitored by remote gauges mounted on an exterior portion of the trailer. The trucker must stop the truck and get out of the cab to view the gauges. When a refrigeration breakdown occurs, several hours may pass before the trucker discovers the temperature rise when he inspects the gauges. As a practical matter precision readings of refrigeration compartment temperatures are unnecessary. Moreover, an audio and visual signal triggered by a temperature rise over a preselected or predetermined set temperature can hardly be ignored when it is observable within the drivers cab.